Method for forming a cushion

ABSTRACT

A seat cushion mold with an elastic member and method provide the manufacture of an improved seat cushion for use in upholstered chairs or the like having a smooth, uniform shape without unsightly underlines. A thick, resilient foam block is positioned on a rigid planer base and is urged into the mold whereby a thin foam cover layer is adhered to the outer edges of the planar base to produce a precisely contoured cushion which can be upholstered and fitted to a chair frame.

BACKGROUND OF THE INVENTION

[0001] 1. Field Of The Invention

[0002] The present invention pertains to a mold for the formation of seat cushions and particularly for forming a cushion for an upholstered chair seat or the like using a mold having an elastic sheet.

[0003] 2. Description Of The Prior Art And Objectives Of The Invention

[0004] Polyurethane foam and other resilient materials have been used for seat cushions for many years in the upholstered furniture industry. Foam blocks of various dimensions and densities are cut then covered with fabric to form seat cushions for sofas, chairs and other furniture. Additionally, chair and sofa frames are likewise often partially wrapped with resilient foam prior to covering with a selected fabric to achieve the desired contours and appearance. In the cost conscious furniture industry, it has lately been the practice to preassemble foam covered components at various shops which are then assembled at a central plant to expedite the manufacturing process. For example, upholstered chair manufacturers may contract through “outside” sources to purchase a partial chair seat assembly consisting of a wooden base having a contoured foam block glued thereto. The furniture maker, after receiving this partial seat assembly, covers it with a fabric and subsequently attaches it to a finished chair frame. A large number of such partial seat assemblies may be kept on hand by the furniture manufacturer so changes to the fabric type or style can be quickly made depending on the customer's needs. While such partial seat assemblies can be made to exact standards, concerns and uniformity problems arise as the partial seat assembly is subject to an individual upholsterer's ability to correctly tension and attach the fabric cover and any additional layers prior to fixing the fabric cover thereto. The final steps in the chair production are subject to the particular craftsman's skills and oftentimes, by applying too little or too much manual pressure during attachment of the fabric covering, an unacceptable product results. This oftentimes occurs along the upper contours and crown at the top of the seat.

[0005] With the known disadvantages and problems associated with the prior art seat cushion assemblies, the present invention was conceived and one of its objectives is to provide a distortable seat cushion mold that will allow a manufacturer to produce an attractive, uniform and consistent seat on each chair manufactured.

[0006] It is another objective of the present invention to provide a seat cushion that will allow the upholsterer ease and convenience in covering the cushion.

[0007] It is still another objective of the present invention to provide a seat cushion that has no unsightly underlines and one that is contoured evenly throughout.

[0008] It is yet another objective of the present invention to provide a method for forming a seat cushion in which a plurality of synthetic foam components are attached to a rigid base to form a smooth, even crown.

[0009] It is still another objective of the present invention to provide a method for forming a seat cushion whereby a distortable seat cushion mold is used to insure uniformity in the crown.

[0010] It is also another objective of the present invention to provide a seat cushion from the process as described above.

[0011] Various other objectives and advantages of the present invention become apparent to those skilled in the art as a more detailed presentation of the invention is set forth below.

SUMMARY OF THE INVENTION

[0012] The invention herein pertains to a seat cushion mold, a method for using the mold to form a cushion for a chair seat or the like and the product formed therefrom. The mold includes an elastic sheet which is distortable downwardly into a concave shape. The method of forming the cushion comprises contacting at least one foam block by a rigid planar base. Next, a thin foam layer is positioned over the foam block. The planar base, the contacted foam block and the thin foam layer are then positioned, foam layer side down, atop a mold with an elastic sheet and are pressed downwardly into the elastic sheet by, for example, a hydraulic press, which compresses the foam block into a convex mound within the now stretched, concave elastic sheet. The thin foam layer is then urged against the edges of the planar base while the thin foam layer is being adhesively attached to the base. Afterwards, the extending ends of the thin foam layer are trimmed and a seat cushion is thereby provided which can be upholstered with a desired fabric for later installation into a chair frame.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 shows an exploded cross-sectional view of the invention including seat cushion components consisting of a planar base, foam blocks and a thin foam cover layer above the seat cushion mold;

[0014]FIG. 2 demonstrates seat cushion components of FIG. 1 compressed into the seat cushion mold with the top elastic sheet of the mold distorted downwardly into a concave shape while the foam blocks form an inverted convex cushion crown;

[0015]FIG. 3 illustrates the ends of the thin foam cover layer urged against the edges of the planar base for adhesive attachment thereto;

[0016]FIG. 4 depicts a cross-sectional view of an inverted seat cushion of the invention after removal from the mold;

[0017]FIG. 5 shows an edge of the planar base as covered with adhesive; and

[0018]FIG. 6 illustrates a perspective view of the mold with an inverted seat cushion seen in cross section.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0019] The preferred process of the invention is illustrated in FIGS. 1-6 whereby a planar base formed from one inch thick wood having a solvent based contact cement on the outer edges is placed next to a first relatively large, somewhat rectangular, ¾″ thick polyurethane foam block with a density of 1.5 pounds per cubic foot (P.C.F.) and an indentation load deflection (I.L.D.) of 35 pounds. Planar bases can be first stacked and the edges simultaneously sprayed with a fast drying contact cement. Positioned next to this large foam block is a smaller, somewhat rectangular, 1″ thick polyurethane foam block with a density of 1.8 P.C.F. and an I.L.D. of 40 pounds. Placed next to the smaller foam block is a second large block identical to the first. Contacting the second large block is a relatively thin, somewhat rectangular, ⅜″ thick polyurethane foam cover layer with a density of 2.0 P.C.F. and an I.L.D. of 25 pounds. A contact cement is spread around the top surface along the edges of the cover layer and is allowed to dry. The seat components are then placed on a mold consisting of a ⅛″ thick planar rubber bladder fitted over a wooden frame approxiately 4″ high and 24″ long on each side. Pressure from a vertical ram, such as a pneumatic cylinder press, forces the seat components into the mold whereby the rubber bladder or sheet deflects downwardly approximately 2½″ into a concave shape. The foam components are thus molded into a convex, inverted crown shape corresponding to the concave shape of the deflected rubber bladder. The free ends of the thin foam cover layer are urged against the edges of the planar base and the contact adhesive secures the thin foam cover layer to the planar base edges. Excess free ends of the foam cover layer are then trimmed and the seat cushion which results therefrom is smooth, uniform and ready for fabric covering and attachment to a chair frame.

DETAILED DESCRIPTION OF THE DRAWINGS AND OPERATION OF THE INVENTION

[0020] For a more complete understanding of the invention and the process involved, turning now to the drawings, FIG. 1 illustrates an exploded view of a conventional chair seat cushion 30, as is used in chairs, and seat cushion mold 17 in combination with pressure ram 25 used to form cushion 30. Seat cushion 30 components are shown inverted, as they are used during construction, but of course when assembled and mounted to a completed chair frame or the like, they would be turned over. Seat cushion 30 components include planar base 10 comprising a relatively rigid, one inch thick member having a desired outer configuration which may be square with rounded corners, rectangular or having other shapes as desired and made of plywood, composite board, or other suitable material. Below base 10 in FIG. 1 are first large, relatively low density polyurethane foam block 15, small, higher density polyurethane foam block 14, second large, relatively low density polyurethane foam block 16, and thin polyurethane foam cover layer 20. Cover layer 20 is spread with an adhesive along its top surface, near its edges, such as with a solvent based contact cement 12 (shown in exaggerated amounts for clarity in FIG. 1). Cement 12 is also spread on the outer edges 11 of planar base 10, as shown in FIG. 5.

[0021] As is well known by those skilled in the chair manufacturing art, it is usual to affix foam blocks to a planar seat base and therefore these aspects of the invention, as illustrated in FIG. 1, are conventional. Likewise, it is conventional in the furniture trade to “mix” the density of foam blocks in forming cushions; however, the following structure and steps as shown in FIGS. 1-4 and 6 are new and nonconventional and provide an improved seat cushion. Seat cushion 30 components 10, 14, 15, 16 and 20 are positioned above cushion mold 17, which has a generally square frame and top elastic member 18. Two frame side members 19, 19′ are illustrated in FIGS. 1-4 and frame front member 26 is illutrated in FIG. 6, but as would be understood, another frame member 26′ (not shown) is used to form a back frame member. Planar elastic member 18 may be composed of sheet rubber, fabric or other suitable synthetic or natural elastic materials and is fitted over the top of cushion mold 17 and affixed at the periphery along the outer sides of frame members 19, 19′, 26, and 26′. While mold 17 is seen in rectangular form, other shapes could likewise be utilized.

[0022] In FIG. 2, vertical pressure ram 25 is shown compressing and/or deflecting seat cushion components 10, 15, 14, 16 and 20 downwardly into mold 17 by driving against bottom surface 13 of planar base 10. Pressure ram 25 may be operated by hydraulic, pneumatic, electric or manual means as is conventional. Elastic member 18 is stretched and deflected downwardly approximately 2½″ into a concave shape (FIG. 2) that molds and shapes foam components 15, 14, 16 and 20 into a convex, inverted crown 29 (FIG. 6), which corresponds to the contour of deflected elastic member 18.

[0023]FIG. 3 illustrates free ends 22, 22′ of foam cover layer 20 urged against edges 11 of planar base 10 and joined thereto by previously applied contact cement 12. As would be understood, ram 25 causes elastic members 18 to deflect downwardly and outwardly, whereas planar vertical inside walls 28, 28′ of frame member 19, 19′ limit the outward or horizontal deflection. Contact cement 12 may be solvent or water based and other suitable adhesives may also be used. As would be understood, all four ends of cover layer 20 are forced against the outer vertical edges 11 of planar base 10 and the figures herein, except for FIG. 6, show only two edges in cross-sectional view for clarity. FIG. 6 also shows back free end 27 attached to edge 11 of planar base 10. (Front free end 27′ is not shown.) As seen in FIG. 3, free ends 26, 26′ of foam cover layer 20 are lastly trimmed by knife 24 or the like to thereby complete the formation of seat cushion 23, as seen in FIGS. 4 and 6 with base 10 covered completely with the exception of its bottom surface 13. FIGS. 4 and 6 also illustrate elastic sheet 18 of mold 17 having rebounded into its original planar shape upon removal of completed seat cushion 23. Seat cushion 23, as completed, is now available for covering with a fabric or for other treatment prior to incorporation into a chair frame.

[0024] The mold and method as shown herein provide high production capacity while allowing the densities of the seat cushions to be easily varied. The outer shape of finished seat cushion 23 is consistent from cushion to cushion due to the design of mold 17. The method as described herein reduces operator fatigue and the possibility of carpal tunnel syndrome of the workers.

[0025] As would be understood, other shapes and types of cushions can likewise be formed from processes shown herein using different materials and the illustrations and examples are used for explanatory purposes and are not intended to limit the scope of the appended claims. 

I claim:
 1. A cushion mold for forming a resilient seat cushion having a crown from a compressible material comprising: a rigid frame, an elastic member, said elastic member attached to said frame, said elastic member deflectable from said frame, said frame comprising a vertical inside wall, said vertical inside wall positioned to contact said elastic member upon deflection, said inside vertical wall to limit the deflection of said elastic member.
 2. The mold of claim 1 wherein said elastic member is attached to the periphery of said frame.
 3. The mold of claim 1 wherein said frame and said elastic member are substantially rectangular.
 4. The mold of claim 1 wherein said elastic member comprises a relatively thin, resilient rubber sheet.
 5. The mold of claim 1 wherein said elastic member is downwardly deflectable into a concave shape.
 6. The mold of claim 5 wherein said frame has a height greater than the downward deflection of said elastic member.
 7. A method for forming a cushion using a mold having an elastic member comprising the steps of: (a) placing a resilient block in contact with a planar base; (b) positioning a cover layer over the resilient block; (c) placing said cover layer, resilient block, and planar base on said elastic member; (d) urging the planar base downwardly thereby forcing the cover member, resilient block, and planar base into said mold; and (e) deflecting the elastic member downwardly to thereby mold the cover layer and the resilient block.
 8. The method of claim 7 and including the step of attaching the edges of the cover layer to the edges of the planar base.
 9. The method of claim 7 wherein the step of placing a resilient block in contact with a planar base comprises the step of lacing a plurality of resilient blocks proximate said planar base.
 10. The method of claim 9 wherein the step of placing a plurality of resilient blocks comprises the step of placing two relatively large resilient blocks and one relatively small resilient block proximate the planar base.
 11. The method of claim 10 wherein the step of placing two large blocks and one small block comprises the step of sandwiching the small block between the two large blocks.
 12. A method of forming a seat cushion using a mold having a downwardly deflectable planar elastic member attached at its edges to the periphery of the top of a frame, comprising the steps of: (a) placing a first large resilient block in contact with a rigid planar base; (b) placing a smaller resilient block over the first large block with the ends of the first large block extending past the ends of the small block; (c) placing a second large resilient block over the small block with the ends of the second large block extending past the ends of the small block; (d) placing a thin resilient cover layer over the second large block with the ends of the cover layer extending beyond the planar base; (e) placing said blocks on the mold; and (f) urging the planar base downwardly to force the resilient cover layer, resilient blocks, and the planar base into the mold.
 13. The method of claim 12 and including the step of deflecting the elastic member of the mold downwardly into a concave configuration to thereby mold the resilient cover and resilient blocks into a convex shape corresponding to the concave shape of the resilient member.
 14. The method of claim 12 and including the steps of urging the ends of the resilient cover against the edges of the planar base and attaching the ends of the resilient cover to the edges of the planar base to form a seat cushion.
 15. The method of claim 11 and including the step of attaching the cover layer to the planar base.
 16. The method of claim 15 wherein the step of attaching the cover layer to the edges of the planar base comprises the step of gluing the cover layer to the edges of the planar base.
 17. The method of claim 12 and including the step of trimming the edges of the cover layer coincidentally with the edges of the planar base.
 18. The product formed by the method of claim 7 .
 19. The product formed by the method of claim 11 .
 20. A seat cushion mold having an elastic member and a means to deflect the elastic member comprising in combination: a mold frame, said elastic member comprising a thin sheet, said sheet attached across said frame, said deflecting means positioned proximate said elastic member for urging seat cushion components against said elastic member to thereby form a seat cushion. 